/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.naming;

import javax.naming.*;
import java.util.Hashtable;

/**
 * Catalina JNDI Context implementation.
 *
 * @author Remy Maucherat
 */
public class SelectorContext implements Context {


	// -------------------------------------------------------------- Constants

	/**
	 * Namespace URL.
	 */
	public static final String prefix = "java:";

	/**
	 * Namespace URL length.
	 */
	public static final int prefixLength = prefix.length();

	/**
	 * Initial context prefix.
	 */
	public static final String IC_PREFIX = "IC_";
	/**
	 * The string manager for this package.
	 */
	protected static final StringManager sm = StringManager.getManager(Constants.Package);

	// ----------------------------------------------------------- Constructors
	private static final org.apache.juli.logging.Log log =
			org.apache.juli.logging.LogFactory.getLog(SelectorContext.class);
	/**
	 * Environment.
	 */
	protected Hashtable<String, Object> env;


	// ----------------------------------------------------- Instance Variables
	/**
	 * Request for an initial context.
	 */
	protected boolean initialContext = false;

	/**
	 * Builds a Catalina selector context using the given environment.
	 */
	public SelectorContext(Hashtable<String, Object> env) {
		this.env = env;
	}

	/**
	 * Builds a Catalina selector context using the given environment.
	 */
	public SelectorContext(Hashtable<String, Object> env,
	                       boolean initialContext) {
		this(env);
		this.initialContext = initialContext;
	}


	// --------------------------------------------------------- Public Methods


	// -------------------------------------------------------- Context Methods

	/**
	 * Retrieves the named object. If name is empty, returns a new instance
	 * of this context (which represents the same naming context as this
	 * context, but its environment may be modified independently and it may
	 * be accessed concurrently).
	 *
	 * @param name the name of the object to look up
	 * @return the object bound to name
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public Object lookup(Name name)
			throws NamingException {

		if (log.isDebugEnabled()) {
			log.debug(sm.getString("selectorContext.methodUsingName", "lookup",
					name));
		}

		// Strip the URL header
		// Find the appropriate NamingContext according to the current bindings
		// Execute the lookup on that context
		return getBoundContext().lookup(parseName(name));
	}

	/**
	 * Retrieves the named object.
	 *
	 * @param name the name of the object to look up
	 * @return the object bound to name
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public Object lookup(String name)
			throws NamingException {

		if (log.isDebugEnabled()) {
			log.debug(sm.getString("selectorContext.methodUsingString", "lookup",
					name));
		}

		// Strip the URL header
		// Find the appropriate NamingContext according to the current bindings
		// Execute the lookup on that context
		return getBoundContext().lookup(parseName(name));
	}

	/**
	 * Binds a name to an object. All intermediate contexts and the target
	 * context (that named by all but terminal atomic component of the name)
	 * must already exist.
	 *
	 * @param name the name to bind; may not be empty
	 * @param obj  the object to bind; possibly null
	 * @throws javax.naming.NameAlreadyBoundException            if name is already
	 *                                                           bound
	 * @throws javax.naming.directory.InvalidAttributesException if object did not
	 *                                                           supply all mandatory attributes
	 * @throws NamingException                                   if a naming exception is encountered
	 */
	@Override
	public void bind(Name name, Object obj)
			throws NamingException {
		getBoundContext().bind(parseName(name), obj);
	}

	/**
	 * Binds a name to an object.
	 *
	 * @param name the name to bind; may not be empty
	 * @param obj  the object to bind; possibly null
	 * @throws javax.naming.NameAlreadyBoundException            if name is already
	 *                                                           bound
	 * @throws javax.naming.directory.InvalidAttributesException if object did not
	 *                                                           supply all mandatory attributes
	 * @throws NamingException                                   if a naming exception is encountered
	 */
	@Override
	public void bind(String name, Object obj)
			throws NamingException {
		getBoundContext().bind(parseName(name), obj);
	}

	/**
	 * Binds a name to an object, overwriting any existing binding. All
	 * intermediate contexts and the target context (that named by all but
	 * terminal atomic component of the name) must already exist.
	 * <p>
	 * If the object is a DirContext, any existing attributes associated with
	 * the name are replaced with those of the object. Otherwise, any
	 * existing attributes associated with the name remain unchanged.
	 *
	 * @param name the name to bind; may not be empty
	 * @param obj  the object to bind; possibly null
	 * @throws javax.naming.directory.InvalidAttributesException if object did not
	 *                                                           supply all mandatory attributes
	 * @throws NamingException                                   if a naming exception is encountered
	 */
	@Override
	public void rebind(Name name, Object obj)
			throws NamingException {
		getBoundContext().rebind(parseName(name), obj);
	}

	/**
	 * Binds a name to an object, overwriting any existing binding.
	 *
	 * @param name the name to bind; may not be empty
	 * @param obj  the object to bind; possibly null
	 * @throws javax.naming.directory.InvalidAttributesException if object did not
	 *                                                           supply all mandatory attributes
	 * @throws NamingException                                   if a naming exception is encountered
	 */
	@Override
	public void rebind(String name, Object obj)
			throws NamingException {
		getBoundContext().rebind(parseName(name), obj);
	}

	/**
	 * Unbinds the named object. Removes the terminal atomic name in name
	 * from the target context--that named by all but the terminal atomic
	 * part of name.
	 * <p>
	 * This method is idempotent. It succeeds even if the terminal atomic
	 * name is not bound in the target context, but throws
	 * NameNotFoundException if any of the intermediate contexts do not exist.
	 *
	 * @param name the name to bind; may not be empty
	 * @throws javax.naming    NameNotFoundException if an intermediate context
	 *                         does not exist
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public void unbind(Name name)
			throws NamingException {
		getBoundContext().unbind(parseName(name));
	}

	/**
	 * Unbinds the named object.
	 *
	 * @param name the name to bind; may not be empty
	 * @throws javax.naming    NameNotFoundException if an intermediate context
	 *                         does not exist
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public void unbind(String name)
			throws NamingException {
		getBoundContext().unbind(parseName(name));
	}

	/**
	 * Binds a new name to the object bound to an old name, and unbinds the
	 * old name. Both names are relative to this context. Any attributes
	 * associated with the old name become associated with the new name.
	 * Intermediate contexts of the old name are not changed.
	 *
	 * @param oldName the name of the existing binding; may not be empty
	 * @param newName the name of the new binding; may not be empty
	 * @throws javax.naming.NameAlreadyBoundException if name is already
	 *                                                bound
	 * @throws NamingException                        if a naming exception is encountered
	 */
	@Override
	public void rename(Name oldName, Name newName)
			throws NamingException {
		getBoundContext().rename(parseName(oldName), parseName(newName));
	}

	/**
	 * Binds a new name to the object bound to an old name, and unbinds the
	 * old name.
	 *
	 * @param oldName the name of the existing binding; may not be empty
	 * @param newName the name of the new binding; may not be empty
	 * @throws javax.naming.NameAlreadyBoundException if name is already
	 *                                                bound
	 * @throws NamingException                        if a naming exception is encountered
	 */
	@Override
	public void rename(String oldName, String newName)
			throws NamingException {
		getBoundContext().rename(parseName(oldName), parseName(newName));
	}

	/**
	 * Enumerates the names bound in the named context, along with the class
	 * names of objects bound to them. The contents of any subcontexts are
	 * not included.
	 * <p>
	 * If a binding is added to or removed from this context, its effect on
	 * an enumeration previously returned is undefined.
	 *
	 * @param name the name of the context to list
	 * @return an enumeration of the names and class names of the bindings in
	 * this context. Each element of the enumeration is of type NameClassPair.
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public NamingEnumeration<NameClassPair> list(Name name)
			throws NamingException {

		if (log.isDebugEnabled()) {
			log.debug(sm.getString("selectorContext.methodUsingName", "list",
					name));
		}

		return getBoundContext().list(parseName(name));
	}

	/**
	 * Enumerates the names bound in the named context, along with the class
	 * names of objects bound to them.
	 *
	 * @param name the name of the context to list
	 * @return an enumeration of the names and class names of the bindings in
	 * this context. Each element of the enumeration is of type NameClassPair.
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public NamingEnumeration<NameClassPair> list(String name)
			throws NamingException {

		if (log.isDebugEnabled()) {
			log.debug(sm.getString("selectorContext.methodUsingString", "list",
					name));
		}

		return getBoundContext().list(parseName(name));
	}

	/**
	 * Enumerates the names bound in the named context, along with the
	 * objects bound to them. The contents of any subcontexts are not
	 * included.
	 * <p>
	 * If a binding is added to or removed from this context, its effect on
	 * an enumeration previously returned is undefined.
	 *
	 * @param name the name of the context to list
	 * @return an enumeration of the bindings in this context.
	 * Each element of the enumeration is of type Binding.
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public NamingEnumeration<Binding> listBindings(Name name)
			throws NamingException {

		if (log.isDebugEnabled()) {
			log.debug(sm.getString("selectorContext.methodUsingName",
					"listBindings", name));
		}

		return getBoundContext().listBindings(parseName(name));
	}

	/**
	 * Enumerates the names bound in the named context, along with the
	 * objects bound to them.
	 *
	 * @param name the name of the context to list
	 * @return an enumeration of the bindings in this context.
	 * Each element of the enumeration is of type Binding.
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public NamingEnumeration<Binding> listBindings(String name)
			throws NamingException {

		if (log.isDebugEnabled()) {
			log.debug(sm.getString("selectorContext.methodUsingString",
					"listBindings", name));
		}

		return getBoundContext().listBindings(parseName(name));
	}

	/**
	 * Destroys the named context and removes it from the namespace. Any
	 * attributes associated with the name are also removed. Intermediate
	 * contexts are not destroyed.
	 * <p>
	 * This method is idempotent. It succeeds even if the terminal atomic
	 * name is not bound in the target context, but throws
	 * NameNotFoundException if any of the intermediate contexts do not exist.
	 * <p>
	 * In a federated naming system, a context from one naming system may be
	 * bound to a name in another. One can subsequently look up and perform
	 * operations on the foreign context using a composite name. However, an
	 * attempt destroy the context using this composite name will fail with
	 * NotContextException, because the foreign context is not a "subcontext"
	 * of the context in which it is bound. Instead, use unbind() to remove
	 * the binding of the foreign context. Destroying the foreign context
	 * requires that the destroySubcontext() be performed on a context from
	 * the foreign context's "native" naming system.
	 *
	 * @param name the name of the context to be destroyed; may not be empty
	 * @throws javax.naming                     NameNotFoundException if an intermediate context
	 *                                          does not exist
	 * @throws javax.naming.NotContextException if the name is bound but does
	 *                                          not name a context, or does not name a context of the appropriate type
	 */
	@Override
	public void destroySubcontext(Name name)
			throws NamingException {
		getBoundContext().destroySubcontext(parseName(name));
	}

	/**
	 * Destroys the named context and removes it from the namespace.
	 *
	 * @param name the name of the context to be destroyed; may not be empty
	 * @throws javax.naming                     NameNotFoundException if an intermediate context
	 *                                          does not exist
	 * @throws javax.naming.NotContextException if the name is bound but does
	 *                                          not name a context, or does not name a context of the appropriate type
	 */
	@Override
	public void destroySubcontext(String name)
			throws NamingException {
		getBoundContext().destroySubcontext(parseName(name));
	}

	/**
	 * Creates and binds a new context. Creates a new context with the given
	 * name and binds it in the target context (that named by all but
	 * terminal atomic component of the name). All intermediate contexts and
	 * the target context must already exist.
	 *
	 * @param name the name of the context to create; may not be empty
	 * @return the newly created context
	 * @throws javax.naming.NameAlreadyBoundException            if name is already
	 *                                                           bound
	 * @throws javax.naming.directory.InvalidAttributesException if creation of the
	 *                                                           sub-context requires specification of mandatory attributes
	 * @throws NamingException                                   if a naming exception is encountered
	 */
	@Override
	public Context createSubcontext(Name name)
			throws NamingException {
		return getBoundContext().createSubcontext(parseName(name));
	}

	/**
	 * Creates and binds a new context.
	 *
	 * @param name the name of the context to create; may not be empty
	 * @return the newly created context
	 * @throws javax.naming.NameAlreadyBoundException            if name is already
	 *                                                           bound
	 * @throws javax.naming.directory.InvalidAttributesException if creation of the
	 *                                                           sub-context requires specification of mandatory attributes
	 * @throws NamingException                                   if a naming exception is encountered
	 */
	@Override
	public Context createSubcontext(String name)
			throws NamingException {
		return getBoundContext().createSubcontext(parseName(name));
	}

	/**
	 * Retrieves the named object, following links except for the terminal
	 * atomic component of the name. If the object bound to name is not a
	 * link, returns the object itself.
	 *
	 * @param name the name of the object to look up
	 * @return the object bound to name, not following the terminal link
	 * (if any).
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public Object lookupLink(Name name)
			throws NamingException {

		if (log.isDebugEnabled()) {
			log.debug(sm.getString("selectorContext.methodUsingName",
					"lookupLink", name));
		}

		return getBoundContext().lookupLink(parseName(name));
	}

	/**
	 * Retrieves the named object, following links except for the terminal
	 * atomic component of the name.
	 *
	 * @param name the name of the object to look up
	 * @return the object bound to name, not following the terminal link
	 * (if any).
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public Object lookupLink(String name)
			throws NamingException {

		if (log.isDebugEnabled()) {
			log.debug(sm.getString("selectorContext.methodUsingString",
					"lookupLink", name));
		}

		return getBoundContext().lookupLink(parseName(name));
	}

	/**
	 * Retrieves the parser associated with the named context. In a
	 * federation of namespaces, different naming systems will parse names
	 * differently. This method allows an application to get a parser for
	 * parsing names into their atomic components using the naming convention
	 * of a particular naming system. Within any single naming system,
	 * NameParser objects returned by this method must be equal (using the
	 * equals() test).
	 *
	 * @param name the name of the context from which to get the parser
	 * @return a name parser that can parse compound names into their atomic
	 * components
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public NameParser getNameParser(Name name)
			throws NamingException {
		return getBoundContext().getNameParser(parseName(name));
	}

	/**
	 * Retrieves the parser associated with the named context.
	 *
	 * @param name the name of the context from which to get the parser
	 * @return a name parser that can parse compound names into their atomic
	 * components
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public NameParser getNameParser(String name)
			throws NamingException {
		return getBoundContext().getNameParser(parseName(name));
	}

	/**
	 * Composes the name of this context with a name relative to this context.
	 * <p>
	 * Given a name (name) relative to this context, and the name (prefix)
	 * of this context relative to one of its ancestors, this method returns
	 * the composition of the two names using the syntax appropriate for the
	 * naming system(s) involved. That is, if name names an object relative
	 * to this context, the result is the name of the same object, but
	 * relative to the ancestor context. None of the names may be null.
	 *
	 * @param name   a name relative to this context
	 * @param prefix the name of this context relative to one of its ancestors
	 * @return the composition of prefix and name
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public Name composeName(Name name, Name prefix)
			throws NamingException {
		Name prefixClone = (Name) prefix.clone();
		return prefixClone.addAll(name);
	}

	/**
	 * Composes the name of this context with a name relative to this context.
	 *
	 * @param name   a name relative to this context
	 * @param prefix the name of this context relative to one of its ancestors
	 * @return the composition of prefix and name
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public String composeName(String name, String prefix)
			throws NamingException {
		return prefix + "/" + name;
	}

	/**
	 * Adds a new environment property to the environment of this context. If
	 * the property already exists, its value is overwritten.
	 *
	 * @param propName the name of the environment property to add; may not
	 *                 be null
	 * @param propVal  the value of the property to add; may not be null
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public Object addToEnvironment(String propName, Object propVal)
			throws NamingException {
		return getBoundContext().addToEnvironment(propName, propVal);
	}

	/**
	 * Removes an environment property from the environment of this context.
	 *
	 * @param propName the name of the environment property to remove;
	 *                 may not be null
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public Object removeFromEnvironment(String propName)
			throws NamingException {
		return getBoundContext().removeFromEnvironment(propName);
	}

	/**
	 * Retrieves the environment in effect for this context. See class
	 * description for more details on environment properties.
	 * The caller should not make any changes to the object returned: their
	 * effect on the context is undefined. The environment of this context
	 * may be changed using addToEnvironment() and removeFromEnvironment().
	 *
	 * @return the environment of this context; never null
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public Hashtable<?, ?> getEnvironment()
			throws NamingException {
		return getBoundContext().getEnvironment();
	}

	/**
	 * Closes this context. This method releases this context's resources
	 * immediately, instead of waiting for them to be released automatically
	 * by the garbage collector.
	 * This method is idempotent: invoking it on a context that has already
	 * been closed has no effect. Invoking any other method on a closed
	 * context is not allowed, and results in undefined behaviour.
	 *
	 * @throws NamingException if a naming exception is encountered
	 */
	@Override
	public void close()
			throws NamingException {
		getBoundContext().close();
	}

	/**
	 * Retrieves the full name of this context within its own namespace.
	 * <p>
	 * Many naming services have a notion of a "full name" for objects in
	 * their respective namespaces. For example, an LDAP entry has a
	 * distinguished name, and a DNS record has a fully qualified name. This
	 * method allows the client application to retrieve this name. The string
	 * returned by this method is not a JNDI composite name and should not be
	 * passed directly to context methods. In naming systems for which the
	 * notion of full name does not make sense,
	 * OperationNotSupportedException is thrown.
	 *
	 * @return this context's name in its own namespace; never null
	 * @throws javax.naming.OperationNotSupportedException if the naming
	 *                                                     system does not have the notion of a full name
	 * @throws NamingException                             if a naming exception is encountered
	 */
	@Override
	public String getNameInNamespace()
			throws NamingException {
		return prefix;
	}


	// ------------------------------------------------------ Protected Methods

	/**
	 * Get the bound context.
	 */
	protected Context getBoundContext()
			throws NamingException {

		if (initialContext) {
			String ICName = IC_PREFIX;
			if (ContextBindings.isThreadBound()) {
				ICName += ContextBindings.getThreadName();
			} else if (ContextBindings.isClassLoaderBound()) {
				ICName += ContextBindings.getClassLoaderName();
			}
			Context initialContext = ContextBindings.getContext(ICName);
			if (initialContext == null) {
				// Allocating a new context and binding it to the appropriate
				// name
				initialContext = new NamingContext(env, ICName);
				ContextBindings.bindContext(ICName, initialContext);
			}
			return initialContext;
		} else {
			if (ContextBindings.isThreadBound()) {
				return ContextBindings.getThread();
			} else {
				return ContextBindings.getClassLoader();
			}
		}

	}

	/**
	 * Strips the URL header.
	 *
	 * @return the parsed name
	 * @throws NamingException if there is no "java:" header or if no
	 *                         naming context has been bound to this thread
	 */
	protected String parseName(String name)
			throws NamingException {

		if ((!initialContext) && (name.startsWith(prefix))) {
			return (name.substring(prefixLength));
		} else {
			if (initialContext) {
				return (name);
			} else {
				throw new NamingException
						(sm.getString("selectorContext.noJavaUrl"));
			}
		}

	}

	/**
	 * Strips the URL header.
	 *
	 * @return the parsed name
	 * @throws NamingException if there is no "java:" header or if no
	 *                         naming context has been bound to this thread
	 */
	protected Name parseName(Name name)
			throws NamingException {

		if (!initialContext && !name.isEmpty() &&
				name.get(0).startsWith(prefix)) {
			if (name.get(0).equals(prefix)) {
				return name.getSuffix(1);
			} else {
				Name result = name.getSuffix(1);
				result.add(0, name.get(0).substring(prefixLength));
				return result;
			}
		} else {
			if (initialContext) {
				return name;
			} else {
				throw new NamingException(
						sm.getString("selectorContext.noJavaUrl"));
			}
		}

	}


}

